/*
 * DragSource.cs - Add drag source functionality to an FluentListView
 *
 * Author: Phillip Piper
 * Date: 2009-03-17 5:15 PM
 *
 * Change log:
 * 2011-03-29   JPP  - Separate OLVDataObject.cs
 * v2.3
 * 2009-07-06   JPP  - Make sure Link is acceptable as an drop effect by default
 *                     (since MS didn't make it part of the 'All' value)
 * v2.2
 * 2009-04-15   JPP  - Separated DragSource.cs into DropSink.cs
 * 2009-03-17   JPP  - Initial version
 * 
 * Copyright (C) 2009-2014 Phillip Piper
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * If you wish to use this code in a closed source application, please contact phillip.piper@gmail.com.
 */

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Drawing2D;
using Fluent.Lists;

namespace Fluent {
	/// <summary>
	/// An IDragSource controls how drag out from the FluentListView will behave
	/// </summary>
	public interface IDragSource {
		/// <summary>
		/// A drag operation is beginning. Return the data object that will be used 
		/// for data transfer. Return null to prevent the drag from starting. The data
		/// object will normally include all the selected objects.
		/// </summary>
		/// <remarks>
		/// The returned object is later passed to the GetAllowedEffect() and EndDrag()
		/// methods.
		/// </remarks>
		/// <param name="olv">What FluentListView is being dragged from.</param>
		/// <param name="button">Which mouse button is down?</param>
		/// <param name="item">What item was directly dragged by the user? There may be more than just this 
		/// item selected.</param>
		/// <returns>The data object that will be used for data transfer. This will often be a subclass
		/// of DataObject, but does not need to be.</returns>
		object StartDrag(AdvancedListView olv, MouseButtons button, OLVListItem item);

		/// <summary>
		/// What operations are possible for this drag? This controls the icon shown during the drag
		/// </summary>
		/// <param name="dragObject">The data object returned by StartDrag()</param>
		/// <returns>A combination of DragDropEffects flags</returns>
		DragDropEffects GetAllowedEffects(object dragObject);

		/// <summary>
		/// The drag operation is complete. Do whatever is necessary to complete the action.
		/// </summary>
		/// <param name="dragObject">The data object returned by StartDrag()</param>
		/// <param name="effect">The value returned from GetAllowedEffects()</param>
		void EndDrag(object dragObject, DragDropEffects effect);
	}

	/// <summary>
	/// A do-nothing implementation of IDragSource that can be safely subclassed.
	/// </summary>
	public class AbstractDragSource : IDragSource {
		#region IDragSource Members

		/// <summary>
		/// See IDragSource documentation
		/// </summary>
		/// <param name="olv"></param>
		/// <param name="button"></param>
		/// <param name="item"></param>
		/// <returns></returns>
		public virtual object StartDrag(AdvancedListView olv, MouseButtons button, OLVListItem item) {
			return null;
		}

		/// <summary>
		/// See IDragSource documentation
		/// </summary>
		/// <param name="data"></param>
		/// <returns></returns>
		public virtual DragDropEffects GetAllowedEffects(object data) {
			return DragDropEffects.None;
		}

		/// <summary>
		/// See IDragSource documentation
		/// </summary>
		/// <param name="dragObject"></param>
		/// <param name="effect"></param>
		public virtual void EndDrag(object dragObject, DragDropEffects effect) {
		}

		#endregion
	}

	/// <summary>
	/// A reasonable implementation of IDragSource that provides normal
	/// drag source functionality. It creates a data object that supports
	/// inter-application dragging of text and HTML representation of 
	/// the dragged rows. It can optionally force a refresh of all dragged
	/// rows when the drag is complete.
	/// </summary>
	/// <remarks>Subclasses can override GetDataObject() to add new
	/// data formats to the data transfer object.</remarks>
	public class SimpleDragSource : IDragSource {
		#region Constructors

		/// <summary>
		/// Construct a SimpleDragSource
		/// </summary>
		public SimpleDragSource() {
		}

		/// <summary>
		/// Construct a SimpleDragSource that refreshes the dragged rows when
		/// the drag is complete
		/// </summary>
		/// <param name="refreshAfterDrop"></param>
		public SimpleDragSource(bool refreshAfterDrop) {
			RefreshAfterDrop = refreshAfterDrop;
		}

		#endregion

		#region Public properties

		/// <summary>
		/// Gets or sets whether the dragged rows should be refreshed when the 
		/// drag operation is complete.
		/// </summary>
		public bool RefreshAfterDrop {
			get => refreshAfterDrop;
			set => refreshAfterDrop = value;
		}

		private bool refreshAfterDrop;

		#endregion

		#region IDragSource Members

		/// <summary>
		/// Create a DataObject when the user does a left mouse drag operation.
		/// See IDragSource for further information.
		/// </summary>
		/// <param name="olv"></param>
		/// <param name="button"></param>
		/// <param name="item"></param>
		/// <returns></returns>
		public virtual object StartDrag(AdvancedListView olv, MouseButtons button, OLVListItem item) {
			// We only drag on left mouse
			if (button != MouseButtons.Left) {
				return null;
			}

			return CreateDataObject(olv);
		}

		/// <summary>
		/// Which operations are allowed in the operation? By default, all operations are supported.
		/// </summary>
		/// <param name="data"></param>
		/// <returns>All opertions are supported</returns>
		public virtual DragDropEffects GetAllowedEffects(object data) {
			return DragDropEffects.All | DragDropEffects.Link; // why didn't MS include 'Link' in 'All'??
		}

		/// <summary>
		/// The drag operation is finished. Refreshe the dragged rows if so configured.
		/// </summary>
		/// <param name="dragObject"></param>
		/// <param name="effect"></param>
		public virtual void EndDrag(object dragObject, DragDropEffects effect) {
			var data = dragObject as OLVDataObject;
			if (data == null) {
				return;
			}

			if (RefreshAfterDrop) {
				data.ListView.RefreshObjects(data.ModelObjects);
			}
		}

		/// <summary>
		/// Create a data object that will be used to as the data object
		/// for the drag operation.
		/// </summary>
		/// <remarks>
		/// Subclasses can override this method add new formats to the data object.
		/// </remarks>
		/// <param name="olv">The FluentListView that is the source of the drag</param>
		/// <returns>A data object for the drag</returns>
		protected virtual object CreateDataObject(AdvancedListView olv) {
			return new OLVDataObject(olv);
		}

		#endregion
	}
}